Cliona deletrix

Cliona delitrix
Scientific classification
Kingdom:	Animalia
Phylum:	Porifera
Class:	Demospongiae
Subclass:	Tetractinomorpha
Order:	Hadromerida
Family:	Clionaidae
Genus:	Cliona
Species:	C. delitrix
Binomial name
Cliona delitrix Pang, 1973

Cliona delitrix is a species of burrowing demosponge belonging to the family Clionaidae. It is found in shallow water in the Caribbean Sea and the Gulf of Mexico.

Cliona delitrix is a burrowing sponge that is also encrusting. It usually grows on a massive coral, not only covering its surface but also burrowing into its interior, but is sometimes found on some other calcareous substrate such as a shell or a limestone rock. It does not normally grow on branching corals. It can grow to a diameter of up to a metre (yard) and has several large openings called osculi, 10 to 30 mm (0.4 to 1.2 in) wide, surrounded by projecting rims and many small raised papillae 2 to 5 mm (0.1 to 0.2 in) wide. The colour is usually red or dark orange.

Cliona delitrix is found in the Caribbean Sea and Gulf of Mexico at depths down to 4 metres (13 ft). Its range extends from Cuba and Mexico south to Venezuela and Brazil. It is abundant in some areas especially where there is organic pollution.

The main corals on which Cliona delitrix grows are Siderastrea siderea, Diploria labyrinthiformis and Montastraea cavernosa. The sponge is a filter feeder, removing bacteria and other organic particles from the current of water sucked in through its many pores by the movement of flagella. There are channels and chambers inside the sponge and the water finds its way through them and exits through the osculi. The zoanthid coral Parazoanthus parasiticus is often found growing on the surface of this sponge.

Cliona delitrix is a hermaphrodite. The male gametes are produced first and get swept out by the water current. If they are sucked into another sponge, fertilisation can take place. The larvae may be brooded for a while inside the sponge but then leave through the osculi and become planktonic. They drift with the current before settling on the seabed. Each one then starts to grows over the surface of whatever it has landed on. It needs calcium to flourish and if it settles on something calcareous like a massive coral, it will secrete acid to dissolve it as well as continuing to grow over the surface. The interior of the coral may be riddled with holes filled with orange spongy material. The sponge kills the part of the coral close to its growing edge. It is an aggressive species and large corals may have the greater part of their surface covered while small individuals may be completely engulfed.

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Wikipedia